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Does Global Warming Help the Case for Airships?

In the alternate worlds of steampunk fiction, glorious airships rule the skies, untroubled by lingering Hindenburg karma or pesky competition from other flying machines. One way that the television show Fringe flags scenes set in its heroes’ antagonistic parallel universe is by showing a New York skyline ornamented with passenger dirigibles (and a World Trade Center that never fell). Airships in our real world may not currently be much more than floating novelties, but enthusiasts for their technology have never given up on the dream of founding a new airship industry built around transporting people and cargo. Whether they can do so is debatable, but one factor that might tip the balance in their favor—perhaps unexpectedly—is climate change.

Last week, Txchnologist magazine published my story about efforts to bring back commercial airships. Many of the projects involve what are more accurately called hybrid airships. Helium inside their rigid or semi-rigid structures gives them some innate buoyancy (or static lift), but most of what holds them in up is aerodynamic lift from air rushing past their broad, flattened fuselages. These hybrids would also often use vertical thrusters to assist with takeoffs and landings, and ground-effect skirts (like hovercraft) as landing gear so that they could put down on either earth or water. (See my story for more details.)

For decades, the proponents of these hybrids and other airships have argued that they would offer huge advantages as cargo transports, particularly in places hard to serve easily or affordably by other means. Trains and trucks can move heavy loads efficiently but somebody has to build tracks and roadways for them to move on. Airfreight is fast but expensive, and somebody has to build runways and other support facilities at each end for the planes. Airships, according to this argument, could offer the best of both worlds: the ability to fly over undeveloped terrain at relatively low cost and to land in clearings rather than on groomed runways.

The example that I’ve almost always heard cited as an application—going back at least to the late ‘70s or early ‘80s, when I first heard it discussed—is using airships to service isolated logging camps in the frozen north. No need to build trucking roads through the intervening difficult terrain at a cost that Barry Prentice, a professor of supply-chain management at the University of Manitoba, has pegged at roughly $1 million per kilometer. No need to disrupt the forests and other wild areas in between those remote sites and the rest of civilization. And given that the hybrid airships can often supposedly fly about three times or more times as far as comparable airplanes on a given amount of fuel, the airships would seemingly be the more environmentally friendly choice.

An argument that I hadn’t heard until recently, however, is that global warming may increase the pressure to find new sources of transportation into Arctic areas.

Over the past 10 years, the [ice road transportation] network in Manitoba has gone from 55 to 60 days of usage to 20 days or less in some years.

A similar contraction of the ice road season is also evident further north in Alaska and the Northwest Territories. In 2006, the Northwest Territories diamond mines needed to airlift 20 per cent of their supplies because the ice road season ended early.

If we fast forward another decade or so, ice roads may not be worth building. How do the remote communities that depend on this transportation system obtain fuel, construction materials and food supplies?

Prentice argues that airships offer a potentially economical alternative to the Sisyphean task of building and maintaining roads. And analogous kinds of arguments can also be developed for deploying airships to sites in mountains, forests and other locations.

I love the idea of resurrecting airships, but my skepticism refuses to be put down easily. The same general arguments for airships have existed for decades, yet vehicles demonstrating their worth for the proposed jobs have never materialized. That fact doesn’t prove anything about airship technology’s viability, but it does make me wonder why businesses didn’t investigate the uses of airships more aggressively long ago if the economic case for them were so compelling.

It also makes me uncomfortable that most of the independent economic analyses favoring airships that I have been able to find in my research seem to lead back to the work by Prentice and his colleagues, or to papers several decades old. Very possibly I’m missing a large body of modern work on the subject, and I have no reason to think that Prentice’s analyses are wrong. Still, it makes me queasy if too many arguments for airships all balance on his work alone. (I’d be happy to be reassured on this point.)

Joseph A. Dick, an aviation consultant whom I quoted in my story and who wrote a piece about airships for ScientificAmerican.com this past May, is more deeply doubtful than I. He says that simple physical arguments first stated by the aeronautical engineering pioneer Theodore von Kármán in 1950 lead to the conclusion that airships move with too much friction relative to other vehicles of comparable speed. They therefore use more power than trains that are roughly as fast, and they are much slower than planes flying at comparable power consumption. That would suggest that airships don’t occupy a happy medium between cheap trains and expensive planes: rather, they’re stuck in an uncomfortably narrow niche.

Sources at companies working on hybrid airships whom I interviewed didn’t debunk Dick’s argument. They just pointed out that the airships under development are primarily aimed at specialized transportation niches where their advantages stand out. The hope is that once the vehicles have proved themselves in those situations, other uses will begin to emerge.

In the end, we most likely won’t know the truth until somebody really builds some of these new hybrid air vehicles and determines their actual performance and operational costs. I’m rooting for the new airship makers to succeed, but even if they fail, I’ll be glad to simply have an end to the speculative argument after so many decades.

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Question for discussion: Technology is often very path dependent: innovations often succeed or fail because of historical developments rather than their intrinsic strengths or weaknesses. If we lived in a world where the Hindenburg never blew up, do you think that today we would already see airships handling these transportation jobs? Or is it more likely that the skeptics are right and that fundamental arguments based on economics and efficiency would have caused them to lose out to other forms of transportation in any case?

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40 comments

I read the scientific American article and wasn’t impressed at all. He simply doesn’t know very much about the subject, unfortunately. He also uses very poor, dated, and non-applicable arguments. The fact is that airships are surrounded with a connotation of disaster or economic ruin, but it doesn’t take much digging to reveal that it was almost never the airship’s faults themselves. The most famous losses were the breaking up of the Shenandoah, the sinkings of the aircraft carriers Akron and Macon, the crash and explosion of Her Majesty’s R101, and of course the Hindenburg disaster. The only crashes, however, that were even remotely the fault of the airship itself was that of the R101 luxury liner. Even then she was being flown in a viscious storm, like many others. In short, they were screwed over by politics, their crews, the weather that their crews unfathomably operated them in, and the fact that they were built at the beginning of the century when EVERYTHING crashed. By the numbers, airships are actually much safer than helicopters.

Economically speaking, they burn far less fuel than airplanes despite carrying vastly more cargo. They displace all other air cargo methods, and are competitive with trucking. The Scientific American graph is grossly inaccurate and directly contradicted by the airship manufacturers themselves, who are obviously the authority here. And the whole argument about helium being too scarce is bunk. As it is at this moment, it’s true, but that’s because Helium is so artificially cheap it’s just now being developed. It’s up to 7% by volume in natural gas, but is ordinarily disposed of. But now large facilities are opening in Qatar and Australia, among others, to utilize it. Not to mention airship-related helium use takes up only 3% of overall helium consumption!

Re-reading Dick’s article(I had read it when it first came out), I notice that his criticism has two majorly flawed points. First, he references a book written in the ’20s about airships which deals with Hybrid airships dismissively, despite the first true Hybrid airship flying in 2006. He goes on to provide no details on why Hybrids aren’t feasible or why something written nearly 90 years ago would be relevant to modern technology when all you have to do is look at the cover of 1950’s Popular Mechanics magazines to see that it is the opposite of relevant.

His main criticism comes from the “physics” and “inefficiency” of Hybrid and other airships (unclearly)illustrated by a simple graph. It presupposes efficiency to be a function of various factors including horsepower and drag. It’s particularly laughable once you consider that even with that obviously wrong graph, airships STILL edge out other aircraft in terms of efficiency(I suppose you can only fudge so much). He blithely compares trains and cargo ships to cargo planes and airships of various caliber. Because really, they all use horsepower and drag, right? That means they’re the same thing! Uh, no. According to the experts currently building hybrid airships such as the LEMV, which consumes 10 times less fuel than other surveillance drones, midsize(600 foot) hybrid airships are capable of lifting 200 tons and traveling at 100 mph and doing it far more efficiently and cheaply than cargo planes carrying 20 tons and burning ridiculous amounts of fuel. That sounds pretty efficient to me.

Lastly, he accusingly points out that airships have only barely made increases in speed since before WW2. This is because Hybrid airships have almost double the frontal drag area due to their lifting body shape as opposed to a torpedo shape. The benefits of which obviously outweighing the losses.

Dick’s article pointed out that von Kármán’s article had recently been updated by the Imperial College’s Railway Research Group and included a link to it, as I did at the end of my post. That research group does not seem to regard the analysis as preposterous as you do, and nothing in it seems to alter the basis for Dick’s conclusion. Nor did sources I asked say the analysis was fundamentally wrong; they just argued, in effect, that the place on the diagram that airships occupied still had commercial value for at least certain uses.

Bear in mind that, as I mentioned in my Txchnologist piece, Dick has worked on airship design, so he’s not an ignorant outsider to this field. He has told me that he has repeatedly looked at the public design and performance specs for the new airships and hasn’t seen anything that alters his opinion. Perhaps Dick’s conclusions will prove wrong, and we’ll eventually see that the new airships can do better than he anticipates, as I mentioned. But it looks like someone will have to build and test them appropriately before we know.

If he worked on airship design(are you sure it wasn’t aerostat design?), then why would he use such an obviously wrong graph to make his case that they aren’t efficient?

Also, when I say “obviously wrong”, I don’t mean that the math or anything is false, I mean that it only focuses on one tiny perfomance aspect of the ships, not how they would perform as a whole. And even then they edge out cargo aircraft on the graph, so I’m a bit mystified as to how he reached the conclusion that the whole ship is innately inefficient.

You are quite right, we have to wait and see. I just dont want to dismiss it out of hand based on something so shoddy.

I think that Dick’s point and von Kármán’s original argument, as illustrated by the graph, is that if one wants to compare the efficiencies of different means of cargo transportation, three major factors emerge to make that comparison possible: the mass to be transported, the speed of transport, and the amount of power involved in moving the cargo at that speed. The relation of those factors basically simplifies to a graph of the frictional resistance of the vehicle versus its speed, which is what’s shown. Those may not be the only factors that matter for any given mode of transport but they are the ones that allow the most head-to-head comparisons.

So as the graph shows and as you said, yes, the airships do use less power than cargo aircraft—but the airships are also much slower: roughly comparable to trains and trucks, which are all much less expensive to use. If shippers need to move freight in a hurry, they may be willing to pay the premium of using a cargo plane. But if they are not in a hurry, then anybody contemplating the use of an airship needs to justify spending several times as much as it would take to use rail or trucks.

Obviously, in some situations, trains and trucks are ruled out because there are no railways/roadways. But that’s not true for most freight jobs. Maybe it will then make economic sense to develop airships for what are niche applications. But given that these airships seem to be very expensive to develop, another possibility is that shippers will use big cargo helicopters instead, which may be much less pricey to acquire, can land or hover over much smaller cleared spaces, etc.

That’s what Dick’s graph and argument are saying, and honestly, it’s not particularly controversial. Even the airship makers acknowledge that they don’t envision competing with traditional haulage until after they’ve conquered these more special-case markets. Their hope is that some economies of scale and additional returns on investment will start to kick in. Dick’s point is just that it will always be hard if not impossible for these airships to make a case for themselves in any situation where competing types of freight transport exist. We’ll see.

Why does anyone use air freight in the first place? It’s either for speed, or because trucks, seafreight, or rail can’t access somewhere. So yes, you’re absolutely right. But there is one more thing to consider. Airships(let’s look at a skycat 200, for example) only travel at one-fifth the speed of, say, a C-130 Hercules cargo plane. But they carry ten times as much. So the fuel function must also take into account not just the huge and limiting amount of fuel burned and time wasted by the plane to get there, but also make the trip ten more times, there and back again where it only took the airship one trip! The speed advantage therefore evaporates. In a world where fuel is getting so much more limited, that kind of waste will quickly become impossible. Enter the airship. People, of course, will still want to travel by plane, but why not have the bulk air cargo be ruled by the efficient airship?

Joseph A. Dick’s article was correct in the analysis of airship performance, you don’t need a PhD in aerodynamics to work out an airship would have significant drag beyond a certain speed. That speed is around 70kts which translates into a low productivity compared cargo aeroplanes.
The Hybrid designs have a 40% aerodynamic lift, the remaining lift is aerostatic.
We have yet to see any information on exactly how a hybrid airship would unload cargo at the destination.
Although the hover skirt in theory can be run in reverse to suck the vehicle to the ground, can this compensate for off loading the 60% of the remaining aerostatic lift?
How long can this suction be applied before an immediate exchange of ballast of equal weight, we a talking about 12 tons for the smallest hybrid design.

If this ballast is water you require a convenient source, and pumps for transfer. If not water, then earth moving equipment to load soil etc into container bags.
You then require facilities at base to offload the water or the solid ballast that was collected at your destination.
The water would have to be acceptable to the local base environment i.e. filtered; sterile etc. solid ballast will require transport and disposal.
All these operations at destination require equipment and people on the ground who will themselves need basic facilities. How do these get to your destination if there are no roads? If you have a road why do you need an airship!

These and other questions require answers for any cargo operation.

For long endurance surveillance roles the airship or hybrid is well suited that is why they have been selected for the LEMV contract, not for cargo.

Seriously!? Do I have to explain this again? Not cool, dude.
1: Your math is wrong. You take 60/40 aerostatic to aerodynamic lift and apply it to the cargo payload of a miniature hybrid airship, 20 tons. You then come up with the figure of 12 tons of lift needing to be compensated for. WRONG! Where exactly does the actual weight of the ship come into the equation? Did they actually manage to manufacture a ship that weighs NOTHING? Even a goodyear blimp weighs several tons. And where exactly do they say that the the 60% total lift from helium lifts 60% OF THE CARGO? The real figure could be 30%. Or 15%. Whatever it is, it sure as hell is less than what you make it out to be.

2: For the last time, the hovercraft are not the only thing that they use to keep it down! It can compensate for lost fuel weight by using condensers during flight, it has vectorable engines that can be pointed down, you can put some weight on it such as fuel for the journey back(added to the weight of the fuel condensed in flight), put cargo on it for the journey back, and lastly it has the hovercraft. And those are JUST the options it already has, there are even more ways to keep an airship down! Lastly, you provide no good reason as to why the hovercraft can’t hold down signifigantly less than 12 tons, other than you just don’t think they can.

Weight of hybrid approx 10 tons (with 20% for ballonet volume)
So for a full load of cargo (20 tons) as stated 10 tons of ballast is required on delivery. Only if you deliver 8 tons of cargo do you not require ballast. Engine thrust accounts for +/- 2.5 tons.
Sucking the hover skirt requires energy which makes the hybrid lighter and what happens to all the debris being sucked up?

Condensing engine exhaust compensates for fuel burn it does not add weight.

Please explain where the FUEL or CARGO to re-ballast for the return trip comes from. Does it get there by road?
If so we don’t need an airship!

Fine. You want to be that way, at least get your facts straight. Copied off the Hybrid Air Vehicles site:
“Envelope Volume: 32,000 m³ (1,130,000 ft³)
Payload: 20 tonnes (lbs)
Overall Dimensions:
– Length: 81.3 m (268 ft)
– Width: 41.0 m (134 ft)
– Height: 23.9 m (78 ft) Max. Range: 5,200 n.ml Altitude: 9,000 ft Payload Deck Space:
– Length: 22.3 m (70 ft)
– Width: 3.1 m (11 ft)
– Height: 2.7 m (9 ft)
Speed: Cruise 78 KTAS
Maximum: 92 KTAS”
See the difference? You understate the speed, in line with your bizarre insistence that airships can’t feasibly break 70kts(ever hear of the USS Akron??). And you still desperately cling to the falsehood that the aerostatic payload adds up to 12 tons. Here’s another quote from the website: “The hull’s aerodynamic shape, an elliptical cross-section allied to a cambered longitudinal shape, provides up to 40% of the vehicle’s lift.” READ: the VEHICLE’S. As in total lift. Not “Lifts up to 40% of the payload”, but “lifts up to 40% of the vehicle.” The aerostatic lift provides 60% of the airship’s loaded weight. That means that when the thing has landed, it’s 40% TOTAL heavier than air, see? And the total weight of the ship is obviously far greater than just the payload. So when you’re offloading the ship, you still have all the weight of the ship and it’s condensed ballast, remaining fuel, etc. holding it down. It will probably still be somewhat lighter than air, but nothing that one of the plethora of options it has of keeping down won’t fix. So stop claiming that the only weight being hoisted aloft by 40% of the vehicle’s total lift is just 8 tons of the vehicle’s payload!

And your transparent attempt at deflection using the hovercraft question doesn’t work. You still haven’t answered why the hovercraft arent enough to hold down a few remaining tons of lift aside from your insistence that they simply can’t. But to answer that question, maybe there’s some sort of crazily advanced method of allowing air to pass through while deflecting debris! Oh, if only we had the technology to prevent undesireable things from being pulled into engines!/sarcasm.

I never said that weight is added when you condense fuel. It just helps by not letting that weight be lost. Also, there’s no rule that says that same ballast has to be lost when adding fuel for the return flight on site. Enough to make the ship heavy, perhaps??

Presumably the airship would be delivering cargo to SOMETHING, like a logging town or ore and oil refinery. WHY can’t the airship be used to deliver some of the site’s products to the rest of the world? That argument makes zero sense. You CAN be isolated from roads and still have fuel and an economy, dumbass. And the presence of roads or rail would hardly matter anyway because in that case ALL air cargo, planes, choppers, and even airships would be superfluous. But even then, those cost billions and billions, and can’t be operated all year round. So the airships could STILL maintain a niche.

Quote from Skycat presentation ISO Polar 2002
“SkyCat can vertically take off and land at 60 percent of their max gross payload weight”

The 75 kts is not the max speed an airship can fly, but beyond this the fuel consumption becomes significant.
You can operate an airship with ground handling facilities anywhere
but these need to be in place first, even for a hybrid.
Without these your cargo carrying is limited.

@LTA
That data is not currently on their website, Hybrid Air Vehicles. But if so, so what? IF they can take off and land vertically with 12 tons of payload, that doesn’t mean they’re operating lighter than air. Vectored thrust, remember? That accounts for + or – 25% of their total weight, according to the web site. And then you have the hovercraft also pitching in as well(although that might already be counted with the vectored thrust, idk). Besides that, it wouldn’t change the Hybrid’s ability to stay on the ground at all, now would it?

And yes, you can’t just drop off your cargo in the middle of the ocean or Gobi Desert or whatever, not because the Hybrid would fly off uncontrollably, but because it still needs to refuel and take on whatever cargo it needed to bring back. It’s just more economical that way. You’re treating it like an aid helicopter that parachutes supplies down, when in reality it is supposed to connect them to the wider world, and that goes both ways.

OK I’ve not followed all the lift/ballast arguments, but what’s wrong with sending a couple of blokes abseiling down with some big spikes & a sledge hammer then winching the Airship down. The first trip could take a prefabricated mooring tower/lift structure for cargo transfer.

@Cha0tic
That’s an extremely dangerous idea. Even though a hybrid airship is heavy upon landing(pay attention, LTA. Grrrrr.), if you were to just “take out the keys” and unload all of your cargo, relying only on the mast, the ship WILL eventually become lighter than air. And that’s very, very bad. An airship at mast that’s lighter than air is in the most vulnerable position possible. Airships seem to be allergic to their own mooring towers, the and while airship accidents are rare compared to helicopter and small airplane crashes, the overwhelming amount of accidents and near-accidents that do occur are when a ship is turned off or unmanned at mast.

They eventually get away and drift off. Just off memory, the Total Pole airship was destroyed when it escaped, and the Olympic blimp, and a military aerostat over some suburbs a few weeks ago, a skyship 600 broke away this spring and destroyed ANOTHER nearby anti-nuke/ballistic missile aerostat, the K-74(or was it 113?) escaped Tilamook air station while it was under construction, destroyed, the Goodyear blimp’s various incarnations have had some damage while at mast, a Nan ship was destroyed at mast, the rigid aircraft carrier R-34 “Pulham Pig” broke away and had an extraordinary adventure that eventually led to a daring escape over the North Sea with half her bow missing. There are doubtlessly others that I forget. But my point remains the same, it’s safer and better for all concerned if the ship simply holds itself down of it’s own power while being ballasted or loaded or refueled or whatever it needs to have to make it heavier.

The Hybrid Air Vehicle design has a mooring point on the underside of the bow section! This is for longer term mooring, as stated before the air cushion/suction skirt is for short term landing to allow re-ballasting. All the issues you have stated in your last post will therefore apply to a hybrid. WE must get away from this myth that a hybrid airship solves all the problems of ground handling that beset previous airships.
You can land heavy but if you off load more than aerodynamic lift (calculated as 40% of the total lift or 40% of the payload) you require ballast and a means of loading it.
Loading requires equipment and people to operate it, if these are not in place at the landing site then they have to be part of your payload.
One last point, the current LEMV contract is for one initial hybrid airship with options on two more. The project is attracting attention of the US congress as the Air Force is also spending $200 million on their own airship, why do you need two types?
Defence cuts are pending to tackle the $14.3 Trillion US national debt, this is just the sort of peripheral defence expenditure that will get cut. The LEMV will have to be on time, on budget and have an outstanding performance in Afghanistan, and all that assuming the troops are not pulled out early as Obama keeps telling us he wants!

@LTA Yes, the LEMV does have a mast option for more flexibility. But that’s more to keep it in place on the ground than to hold it down. What makes you think it will be held at the mast lighter than air? It would make much more sense to land, use the hovercraft/vectored thrust(the LEMV has no hovercraft), load up on ballast, then attach to the mast so that it stays put instead of rolling around on the tarmac. No need to drive stakes when you could just drive some sandbags on board and park it to the mast.

And that second question is stupid on so many levels. How many different kinds of fighter planes and air superiority jets do we have? And how often do they face another fighter jet? How many kinds of cargo plane do we have? Or satellite? Or drone? Variety is everywhere in the military, LTA, even where it isn’t needed. But we DO in fact need airships because their singular capabilities could save billions of dollars! And they do the job better and longer than any satellite, drone, helicopter or jet!

@LTA
YES! They don’t apply! Because this is a HYBRID AIRSHIP we’re talking about! It’s heavy while on the ground! Every last example I mentioned of an airship getting away from the mast happened because they FLEW AWAY! What part of that do you not understand!?

And you haven’t addressed my point. Again. Instead, you try to deflect. Again.

The reason those two programs were defunded was because they were harebrained, pie-in-the-sky projects. The USN surveillance airship was superfluous and unimaginative. Walrus was on the bleeding edge of an unproven technology, it was gargantuan, expensive, and again, there was no real need for it compared to it’s many disadvantages. The LEMV, on the contrary, is a modest, cheap, reliable system based on mature, proven technologies that would fill a very urgently needed niche. Really, aside from the fact that they use Helium, the projects couldn’t be more different.

Why would you need a mooring point if as you state a heavy hybrid airship can hold position on the ground? The problems with mooring airships in high winds as your examples of accidents demonstrate would still apply to a Heavy hybrid. The wind will still exert a force on the envelope of a hybrid as per a conventional airship. Clearly the mooring point is for long term storage and as such will allow the hybrid to keep the bow into wind, which suggests the hybrid would not be in a heavy state.

You seem to be constantly making the assumption that a Hybrid airship solves all the problems that have held airships back for many years. Until you can supply credible evidence for these assumptions they remain just pure speculation.

The “harebrained, pie-in-the-sky projects” were awarded to Airship Industries the precursor of ATG and the current organization Hybrid Air Vehicles. Do you therefore suggest HAV with a core of staff from the 80’,s chase harebrained, pie-in-the-sky projects.

The WALRUS project was the precursor for a heavy lift airship concept which led to the P791 by Lockheed Martin. LM lost out to HAV for the LEMV contract so are LM harebrained?

@LTA
Wrong again. A hybrid airship does not have to be light to require a mast. In an airplane, you can basically just land and walk out. An airship requires the use of a mast, and is obviously always light. Accidents ensue. But as a hybrid between the two, the hybrid airship is a bit of both. Like an airplane, it is heavy, so it avoids the accidents that result from an airship flying away. But like an airship, it has a gargantuan, sail-like hull that in gusts and without power would skitter along the runway. So the mast is there to secure it in place, but not secure it to the GROUND, because it would OBVIOUSLY be heavy! There is NOTHING to suggest it would be held at the mast light!

And yes, they were assigned that project by the military. It was their fault, not Airship Industries’. They did not properly evaluate the need or mission objectives there. So when they did realize that they didn’t even want what they ordered, they backed off. Airship Industries got screwed, end of story. And that was a large blimp, not a hybrid.

The P-791 applicant did borrow a few things from Walrus, sure. But you’re waaaay off base. Walrus was a harebrained, pie-in-the-sky project because of it’s SCALE and APPLICATION, not because it was a hybrid airship.

You can’t fool me, LTA. You use unfounded absolutes and speculate madly, but you can’t obfuscate the great potential that hybrids posses.

You cannot compare an aeroplane to a hybrid airship in terms of behaviour on the ground. Taking the 747 as a typical example, the empty weight is about 200 tonnes with min fuel load and with max payload is 400 tonnes max take off wt. The 20 tonne hybrid airship which is longer than a 747 and with a much greater surface area, would be no more than 10 -12 tonnes heavy. So the idea that something 40 times lighter and with a considerably greater surface area can act like an aeroplane on the ground makes no sense.

As stated before the hybrid requires a mooring point for long term storage and would be subject to all the issues that effect conventional airships even if it is 12 tonnes heavy. Only for the brief periods of cargo exchange is the hover/suction skirt in use.
Airships spend a significant portion of their time on the mast and that is the point which they are most vulnerble. The wild beyond the road locations, which are proposed for hybrid cargo operations will present significant challenges.

@LTA
You’re attacking a strawman. At no point did I say that a hybrid airship behaves like an airplane on the ground. I said that it behaved like something between an airship and an airplane. I was the one that pointed out that the hull would act like a sail, just like an airship. Which is why it requires a mast for long term mooring outside. But the hybrid airship is NOT most vulnerable at the mast because it is not an airship. An airship is constantly trying to rise and fly away. Occasionally it succeeds. It flies up, up, up until it reaches it’s pressure height and helium/hydrogen is automatically vented off until the aircraft loses too much and begins to sink, or it is near neutral buoyancy and is carried away by the wind. Either way, the airship crashes and gets battered against the ground until it is destroyed. This is how almost all mast accidents occur. But a hybrid airship is not trying to fly away at all; it’s firmly on the ground. The mast doesn’t have to prevent it from flying away, it only has to make the hybrid airship stationary. Arguably, the most vulnerable a hybrid would be was taking off and landing in a war zone before climbing to a safe height, not being moored to a mast.

Even if worst came to worst and the hybrid, unmanned, escaped somehow, it would only slooooowly scoot along the ground until it rested up against a boulder or trees or something. Providing it was really windy, of course. And that there wasn’t some sort of back-up to the mast. And there was no-one around to stop the airship. And no-one was minding the airship while it was storming. And it wasn’t sheltered from said storm in the first place, or at least tied down more securely. It wouldn’t be anywhere near as severe as an escaped airship, which would be battered and dragged and speared over and over and over again.

The idea that with a hybrid airship “The mast doesn’t have to prevent it from flying away, it only has to make the hybrid airship stationary” seems bizarre. Surely the reverse hover skirt would perform such a role for brief landing hops. Even the Zeppelin-NT does not use a mast for passenger exchange.
The mooring point on the HAV hybrid is clearly for long term masting, allowing rotation with the wind. It will require the hybrid to be able to move around the ground and thus by relatively light and/or have some sort of landing gear. If as you have stated it can remain heavy on the ground and stationary, they would not have added a mooring point.

As for your statement “ slowly scoot along the ground” with no damage if it became free of the mast. This is simply wrong, it would cause considerable damage to the lower structure unless the hoverskirt was operating.
Thus by your own reasoning the hybrid is no more than a conventional airship for significant parts of it’s ground handling operation.

@LTA
Your arguments are becoming even harder to decipher. Of course it would use the hovercraft to land for short hops. LEMV doesn’t have them though, so I assume we’ve switched back to SkyCats and SkyTugs now. The mast would only be used in instances where it’s nowhere near a hangar and must be stored outside for great lengths of time.

Presumably the inflatable pneumatic landing skids have some sort of wheel on them, considering the P-791 has them clearly visible on it’s ACLS pads. It would indeed have to be able to rotate with the winds, what better way than to just unlock the wheels and let the mast do it’s thing? It’s absurd to assume that it would have to be light just to roll around! By that logic, how do 747s land? They’re much heavier, yet LO AND BEHOLD, their wheels can function!

And it is not “simply wrong” to say the airship would skid across the ground if it got away(in as much that hybrid can even escape it’s mast), what else would it do? Other than sit in place if it wasn’t windy enough, but then how on earth did it get away in the first place? We’ve already established that it would definitely be at the mast heavy, because these people aren’t retarded, and it would have some way of shifting position at mast(read: wheels), so IF one got away somehow, wouldn’t it be rolling along just like it did at mast? And while it was rolling, how would the understructure be damaged? Landing gear is designed to be able to, you know, handle landing. The worst scenario would be if it somehow bypassed the barriers around the landing site and punctured some of it’s gas cells against a line of trees. Even then, the damage would be easily repaired and the hard structure relatively undamaged. But the likelihood of that happening is very small for a hybrid anyway. So small it hardly even warrants discussion, compared to, say, Muslims trying to shoot it down.

Could you please show evidence of a fully functioning undercarriage on a HAV or the P791. Such structures and their internal support would add significant weight to support a heavy hybrid as you keep stating. In all previous airships the undercarriage is small and light, and that is exactly what will be used when a hybrid is parked on the mast long term. The other option would be water landing, requiring a convenient lake or calm sea landing site.

@LTA
Sure thing. If you watch “P-791 Hybrid Air Vehicle”(odd title, ain’t it?), a Lockheed Martin promo video on YouTube, you can see that it rests on these rollers. They’re clearly not a part of the usual structure, and look rather kludgy, but it raises the interesting possibility of having detachable undercarriages for hybrid airships at mast.

Additionally, since most hybrid airships, LEMV notwithstanding, rest upon hovercraft anyway, I don’t see why the hybrid airship shouldn’t capitalize on the preexisting structural integrity and “internal support” there and have some sort of wheel attachment on the hovercraft. It would also have the benefit of providing a strong safety barrier in case of hard landings that might otherwise damage the hovercraft.

As I understand it, recent studies show that the Hindenburg wasn’t a victim of hydrogen, but of the material used to form the blimp being susceptible to ignition by the voltages generated in the atmosphere. Helium is down as one of our the resources we’re running out of, since it comes from natural gas reserves, which ultimately means a return to hydrogen is inevitable to be economically viable. It only needs investment in research into suitable material that will contain hydrogen and not set itself on fire.

@Ryan Bennit
Actually, Hydrogen was indeed the culprit in the Hindenburg disaster. If there was no Hydrogen on board, as she was originally designed for, then fabric or not that fire would never have taken place.

Furthermore, as Helium does indeed come from natural gas, it is a non-renewable rescource, correct. But usage in airships is a minuscule fraction of overall helium use, and most helium isn’t even refined from natural gas(<7% by volume of natural gas is helium), and is released into the atmosphere, which also contains small amounts of unfortunately unattainable(using current methods) helium. And with the new helium refineries opening in Qatar and Australia, it really isn't that big an issue at all. By the time it does get prohibative, we'll probably be able to make it from hydrogen anyway.

But for everything else, yes, hydrogen does deserve a second chance. It's almost 10% more powerful, cheap and abundant, and even in the Great War it was inordinately difficult to get Zeppelins to burn because pure hydrogen is nonflammable. With modern fireproofing, safety measures and materials, it could be made almost as safe as helium. There's also the intruiging possibility of engulfing the Hydrogen bags, as the Hindenburg was proposed to do, or mixing it directly with a nonflammable lift gas such as Nitrogen(albeit N2 is a very weak lift gas due to the mostly nitrogen composition of our atmosphere) in order to render it nonflammable entirely. But unfortunately the Hindenburg disaster has been seared into the public consciousness. I myself was creeped out by confronting the horror personally, in the form of relics from the cruise ship. Therefore in the forseeable future, I predict that IF Hydrogen is used, it will be on UAVs exclusively for a long while yet, and the last place it will be adopted will be by the military and cruise lines.

Hey armchair engineers and airship buffs, do you know if anyone has ever tried tugboating an airship? Either with an airplane that would drag the thing through the skies or with, say, a train or fast ship to drag it along? You know, all old school Erie Canal style, except with boats and miles-long cables instead of mules and skiffs?

@Josh
No, no one has. In fact, just the opposite. In the days before liability suits and such, the little Goodyear blimp has been known to give water-skiers the ride of their lives. During World War One, German Zeppelins would carry small gondolas on half-mile-long cables that would act like cloud periscopes so the Zeppelin could carry out the raid unseen. This was before they could carry fighter planes to scout and battle for them, from the later parts of the war onwards.

Trains and ships are much slower than all but the tiny hot air blimps anyway, so why bother?